Plymouth Duster Suspension/Tubbing Question - Drag Racing

I'm currently working on my 1973 Plymouth Duster 340 and need some advice. To be upfront I am very new to car building and I'm learning as I go. My goal is to build a 10+ second car for the quarter while keeping it a 340.

1) I'm in the process of getting an 8 point roll cage professionally installed and my rear suspension redone. I need to know whether to switch over to a coil over suspension (QA1 drag stage 2 coil over suspension kit is the one I'm considering) or if after market (Mopar Performance Leaf Springs paired with QA1 shocks) will suffice to reach my goal?

2) Does anyone know the max wheel width size a 73' Plymouth Duster can have with a leaf spring relocation done, no mini tub and not have the tire sticking outside the fender?

I'd appreciate any advice. Thank you!